I chopped it off because it was very straight and was going to do some thread grafting to get some branches lower down but every time I go to do it,I am at a loss to know where to put some branches as I think what is left is still very straight

The cut is approx 350mm from the top of the soil so I suppose I could cut again but am worried whether it would reshoot after such drastic action as it would leave no branches at all.
I would appreciate any advice,opinions and virts that you guys can give me, as I am entering unknown territory, with my very limited experience.
Left the knife there when I took the picture for a bit of a laugh and to remind the tree that it has got to come good or else.